If you have a burner, you will need to find a win9x boot image with CDROM support, and then make a bootable CD from the boot image, and include your firmware on the data portion of the CD. But then again, you may not be able to read/write while updating the firmware. ......... :scratch:
Or if you can find a win98 SE CD you should be able to boot off of that with an option for cd support. As for updating the firmware it should allow you to make a bootable disk, instead of making a floppy use that boot image to make a bootable cd. But I agree with Raze, you may not be abel to update the firmware from a bootable cd... ummm, hmm...